Abstract:
Seed health testing to detect seed-borne pathogens is an important step in the management of crop diseases. Laboratory and screen house experiments were carried out at Selian Agriculture Research Institute Arusha, to investigate the extent of seed-borne fungal pathogen problems from farmers saved seeds in Northern wheat growing Zone. A total of 45 untreated seed samples of wheat were collected from farmers saved seeds in Karatu, Hanang and Siha Districts. Each sample was physically inspected and pure seeds were separated from abnormal seeds and inert matter. Seed samples collected at Siha were of high quality compared to seed samples collected at Hanang and Karatu. Pure seeds ranged from 98.2–99.2%, abnormal seeds 0.49–1.4% and inert mater 0.15–0.80%. Alternaria alternata, Bipolaris sorokiniana, Dresclera tritici, Fusarium graminearum, Fusarium moniliforme, Aspergillus flavus, Cladosporium sphaerormum, Epicoccum purpurascers, Pyricularia oryzae and Penicilium Corylophilum were isolated and identified using blotter, potato dextrose agar (PDA) and agar plate methods. The most predominant seed-borne fungi were Cladosporium sphaerormum (9.8%), Alternaria alternata (9.2%) and Aspergillus flavus (8.7%). The lowest percent seed infection (10.5%) was recorded in samples collected at Siha District, (17.5%) at Hanang District and (20.4%) at Karatu District. The percentage fungal seed infection was higher in seed samples collected at Karatu with infection rate of 32.8% and lowest for seeds sample collected at Siha with infection of 25.4%. The overall seed infection in the region was 29.1% causing yield losses of 1.2 t/ha on average. Seed treatment with Metalaxy plus, Mancozeb and Baytan was found to increase percent seed germination by 17.2, 14.3, and 12% respectively and yield by 27.8, 20.4 and 17.8% respectively. Farmers saved seeds in Hanang, Karatu and Siha districts are heavily infected with fungi and it is recommended that they should be treated with appropriate fungicides prior planting.
